import java.net.*;
import java.io.*;

/**
 * Threaded Echo Server, sequential allocation scheme.
 * @author Ian F. Darwin.
 */
public class EchoServerThreaded {

	public static final int ECHOPORT = 7;

	public static void main(String[] av)
	{
		new EchoServerThreaded().runServer();
	}

	public void runServer()
	{
		ServerSocket sock;
		Socket clientSocket;

		try {
			sock = new ServerSocket(ECHOPORT);
		
			System.out.println("EchoServerThreaded ready for connections.");

			/* Wait for a connection */
			while(true){
				clientSocket = sock.accept();
				/* Create a thread to do the communication, and start it */
				new Handler(clientSocket).start();
			}
		} catch(IOException e) {
			/* Crash the server if IO fails. Something bad has happened */
			System.err.println("Could not accept " + e);
			System.exit(1);
		}
	}

	/** A Thread subclass to handle one client conversation. */
	class Handler extends Thread {
		Socket sock;

		Handler(Socket s) {
			sock = s;
		}

		public void run() 
		{
			System.out.println("Socket starting: " + sock);
			try {
				DataInputStream is = new DataInputStream(
					sock.getInputStream());
				PrintStream os = new PrintStream(
					sock.getOutputStream(), true);
				String line;
				while ((line = is.readLine()) != null) {
					os.print(line + "\r\n");
					os.flush();
				}
				sock.close();
			} catch (IOException e) {
				System.out.println("IO Error on socket " + e);
				return;
			}
			System.out.println("Socket ENDED: " + sock);
		}
	}
}